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Seyyed Reza Miri Rostami: Achromatic Extended-Depth-of-Field Imaging with Diffractive Optical Elements

Tampere University
LocationKorkeakoulunkatu 8, Tampere
Hervanta campus, Festia, auditorium Pieni sali 1 (FA032) and remote connection
Date23.10.2024 12.00–16.00 (UTC+3)
LanguageEnglish
Entrance feeFree of charge
The demand for high-quality images is growing rapidly, especially in consumer electronics, bio- and medical imaging, and industrial inspections. Traditional multi-lens camera systems are bulky and often struggle with defocus, chromatic aberrations, limited depth of field, and other various imaging distortions. In his doctoral dissertation, MSc Seyyed Reza Miri Rostami presents a groundbreaking solution to these challenges by developing a hybrid optical system that integrates a refractive lens and diffractive optical elements to achieve achromatic extended depth of field imaging.

The compactness of the diffractive optical elements (DOEs) plays a crucial role in enabling the development of miniature cameras with high performance. Unlike traditional multi-lens setups that require significant space, the DOE allows for a more compact and lightweight design, making it ideal for applications where space is limited but imaging quality cannot be compromised.

MSc Seyyed Reza Miri Rostami focuses on co-designing optical components and image processing algorithms to improve depth of field, image sharpness, and color fidelity. By combining programmable phase spatial light modulators (SLMs) and advanced imaging techniques, the study demonstrates a significant improvement in overall image quality compared to traditional multi-lens systems.

The development of the original Hardware-in-the-Loop (HIL) methodology is one of the key results of the research. This methodology allows us to avoid difficult and unreliable mathematical modeling of image formation in the design and optimization procedures replacing them with physical experiments. This methodology allows real-time optimization of the hybrid imaging system, ensuring that the optical elements (such as the DOE and refractive lens) work seamlessly together with advanced image reconstruction algorithms. The HIL technique also provides automatic compensation for discrepancies between mathematical models and real-world optics, leading to enhanced performance and higher-quality imaging.

The approaches and algorithms developed in this research have a wide range of practical applications, from smartphones and consumer electronics to more specialized fields such as medical imaging, augmented reality (AR), and virtual reality (VR), where compact, high-performance imaging systems are highly valuable.

"By integrating diffractive and refractive elements, and employing the HIL methodology, we can achieve superior image quality without the need for bulky, complex multi-lens setups. This hybrid approach opens up new possibilities for a wide range of imaging applications," Miri Rostami explains.

Seyyed Reza Miri Rostami currently works as an AR waveguide designer at Dispelix Oy, where he applies his expertise in optical systems to the field of augmented reality. His experience in computational imaging and optics design continues to drive innovation in this cutting-edge industry.

Public defence on Wednesday 23 October 

The doctoral dissertation of MSc Seyyed Reza Miri Rostami, titled Achromatic Extended-Depth-of-Field Imaging with Diffractive Optical Elements will be publicly examined at the Faculty of Information Technology and Communication Sciences at Tampere University. The public examination will take place on Wednesday 23 October 2024 at 12:00 at Hervanta campus, in Festia building, auditorium Pieni sali 1 (FA032). The Opponents will be Professor Gonzalo Arce from the University of Delaware, USA, and Dr. Stefano Luigi Oscurato from the University of Naples Federico II, Italy. The Custos will be Professor Karen Eguiazarian, and the co-supervisor of the research is Professor Vladimir Katkovnik, both from Tampere University.

The doctoral dissertation is available online
The public defence can be followed via remote connection